Process of preparing a pouch for packaging flowable materials

Abstract

An environmentally friendly polymer film pouch made from a homogeneously branched substantially linear ethylene interpolymer film structure for the packaging of flowable materials such as milk, the pouch includes, for example, a multilayer film structure such as a two-layer or a three-layer coextruded film containing at least one seal layer of a homogeneously branched substantially linear polyethylene. A process for making a pouch for packaging flowable materials using a homogeneously branched substantially linear ethylene interpolymer film structure is also disclosed.

We claim: 
     
       1. A process of preparing a pouch in a vertical form containing a flowable material comprising the steps of forming a film structure; forming the film structure into a tubular member; heat-sealing longitudinal edges and first transverse end of the tubular member to form the pouch; filling the pouch with the flowable material; and sealing a second transverse end of the tubular member, the film structure having at least one layer comprising: (a) from 10 to 100 percent by weight of at least one homogeneously branched substantially linear ethylene/α-olefin interpolymer, and   (b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a heterogeneously branched linear ethylene/C 3  -C 18  α-olefin copolymer, a high-pressure low density polyethylene and an ethylene/vinyl acetate copolymer.   
     
     
       2. A process of preparing a pouch in a vertical form containing a flowable material comprising the steps of forming a film structure; forming the film structure into a tubular member; heat-sealing longitudinal edges and first transverse end of the tubular member to form the pouch; filling the pouch with the flowable material; and sealing a second transverse end of the tubular member, the film structure having at least one layer comprising: (I) (a) from 10 to 100 percent by weight of at least one homogeneously branched substantially linear ethylene/α-olefin interpolymer, and   (b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a heterogeneously branched linear ethylene/C 3  -C 18  αolefin copolymer, a high-pressure low density polyethylene and an ethylene/vinyl acetate copolymer; and at least one layer comprising:   (II) a heterogeneously branched linear ethylene/C 3  -C 18  α-olefin copolymer having a density greater that about 0.87 g/cm 3  and a melt index from about 0.1 to about 10 g/10 minutes.   
     
     
       3. The process of claim 2 wherein the film structure includes at least one other layer comprising: (III) a high-pressure low density polyethylene having a density from about 0.916 to about 0.93 g/cm 3  and a melt index from about 0.1 to about 10 g/10 minutes.   
     
     
       4. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer is a copolymer of ethylene and a C 3  -C 20  α-olefin. 
     
     
       5. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer is an ethylene/1-octene copolymer. 
     
     
       6. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer is an ethylene/1-hexene copolymer. 
     
     
       7. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer is an ethylene/1-butene copolymer. 
     
     
       8. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer is an ethylene/propene copolymer. 
     
     
       9. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer has a density from about 0.85 g/cm 3  to about 0.94 g/cm 3 . 
     
     
       10. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer has a melt index from about 0.01 g/10 minutes to about 10 g/10 minutes. 
     
     
       11. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer has a I 10  /I 2  ratio from about 7 to about 20. 
     
     
       12. The process of claims 1 or 2 wherein said homogeneously branched Substantially linear ethylene/α-olefin interpolymer has a M w  /M n  from about 1.5 to about 2.5. 
     
     
       13. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer has a M w  /M n  of about 2. 
     
     
       14. The process of claims 1 or 2 wherein said film structure has a heat sealing range from about 50° C. to about 160° C. 
     
     
       15. The process of claims 1 or 2 wherein said film structure has a heat sealing range from about 75° C. to about 130° C. 
     
     
       16. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer has a melting point range from about 50° C. to about 130° C. 
     
     
       17. The process of claims 1 or 2 wherein said homogeneously branched substantially linear ethylene/α-olefin interpolymer has a melting point range from about 55° C. to about 110° C.